Dreaming of dead mother dying again is a warning sign as per dream meaning and interpretation. The dream means you are doing something wrong in your life. Your mother is unhappy with your actions and she is showing it through her death. Symbolically it means if she was alive she would have died out of shame because of your actions.
Dream of dead mother dying again means that you are in some kind of trouble and you need to be cautious about your actions. You should be careful while using vehicles or handling iron and fire.
Dreaming of dead mother dying again and it is through an accident or unnatural death means your enemies will be very active. If your mother had a suspicious death then she is trying to inform you about something.
Please note that the dream to have a meaning it should happen naturally. Thinking about the death of your mother during daytime or just before sleeping and then having the dream has no value.
It is good to visit a worship place and offer prayers for your mother so that her soul rests in peace.